1. Field of the Invention
This invention relates to an endoscope system wherein a common signal processing apparatus can be used for a plurality of types of endoscope apparatuses without inverting images.
2. Related Art Statement
Recently, there is extensively utilized an endoscope whereby organs within a body cavity can be observed by inserting an elongate insertable part into the body cavity or various curing treatments can be made by using treating tools inserted through a treating tool channel as required.
Also, there are suggested various electronic endoscopes using a solid state imaging device such as a charge coupled device (CCD).
Now, there has been a problem that, in the above mentioned electronic endoscopes such as, for example, between a straight viewing endoscope and a side viewing endoscope, the objective optical system is different and therefore, in case the same signal processing is applied, the image of either of the straight viewing endoscope and side viewing endoscope will be inverted. This problem will occur not only in the case of the straight viewing and side viewing but also when the arrangement of this solid state imaging device is changed, for example, by the size of the solid state imaging device or the like.
In order to cope with it, in the publication of a Japanese patent application laid open No. 211040/1987, there is disclosed an endoscope apparatus wherein, so that a common video processing apparatus may be used, an endoscope is provided with a recording means for discriminating the type of endoscope, a signal set in this recording means is discriminated by a discriminating circuit provided in the video processing apparatus and, for the endoscope in which the observed image becomes a mirror image (called also a back image), the image is passed through an image inverting circuit so as to be corrected to a right image.
However, in this related art example, it is necessary to provide an endoscope with a recording means for discriminating the kind of the endoscope and is costly.
Also, it is necessary to incorporate into the video processing circuit an image inverting circuit, endoscope discriminating circuit and switching circuit switching the circuit in response to the type of endoscope and has been a cause of enlarging the video processing apparatus and elevating the cost.
In a U.S. Pat. No. 4,369,459, there is dosclosed a technique wherein an image inverted by an optical member is made a right image by reversing the direction of reading out the solid state imaging device from the normal direction.
However, this prior art is to determine the state of an image in one television camera but does not disclose a means of enabling a plurality of type of endoscopes to be used in a common signal processing apparatus.